Stencil.



I UNITED STATES FRANK D. BELKNAIP, OF NEW YORK, N. Y.

PATENT omen.

STENCIL No Drawing Specification of Letters Patent. Patented J l ne 2-3,1914;. Application filed October 24, 1911. Serial No. 656,851.

Be it known that I, FRANK D. BELKNAP,

- a citizen of the "United States of America,

residing at New York city, county and State of New York, have inventedcertain new and useful Improvements in Stencils, of which the followingis a specification.

My invention" comprises an improved stencil and the sheet from whichsaid stencil may be made by operation of an ordinary typewritingmachine, or similar agency.

The underlying novel feature of m invention is the employment of a'colloid of vegetable origin as the base of a film applied to a sheet ofthin paper of loose and open texture, so as to saturate and incase thefibers of such paper with and in such material. When a sheet of paper sotreated is operated on by an ordinary typewriting machine or with astylus or other device the film of incasing material'is forced aside bythe type blow or stylus point, forming a stencil, across the openings ofwhich the fibers of the .ggtper extend with little or none of thesaturating material adhering to them. Through these openings ordinaryprinting ink will pass, while the remaining portions of the treatedpaper prevent the passage of such ink at any other point. The charactersimpressed on the. stencil sheet are then reproduced on a sheet of paperor the like placed under it, and, when a typewriting machine is used inproducing the stencil, closely resemble ordinary typev writing.Stencils'of this general type have heretofore been produced by coatingpaper; of this kind with animal products such as gelatin or wax, andwith mineral products like paraflin, but these are subject to more orless disadvantages in use. The gelatincoating when used alone or in theform of a compound the principal base of which is gelatin, is so hardand dense that it must be dampened before forming the stencil and thistakes time. The moisture also may rust-the typewriting machine. Thewaxed paper is sticky. The parafiined paper does not give good resultswith a typewriting machine. I have discovered that the use of a colloidof vegetable origin produces a coating far superior for this kind ofwork to those formed by animal or mineral products.

The best method of carrying out. my invention at present known to me isthe followin I take Irish moss, which is a typical ce llcid of vegetableorigin, sometimes called rock moss, which is an ocean product growing onsubmerged rocks and dissolve it in hot water. I find it takes about 14quarts of water to properly dissolve one pound of the moss The water isprefer- 3ounces of glycerin added. Sheetsof J apanese paper calledYoshino paper are saturated and coated with this solution by drawingthem across the surface of the solution, or by applying the solution tothe paper with a. brush, and they are then dried by hanging up in theopen air. The sheets in a solution containing two parts by weight offormaldehyde and one part of glycerin and then given a final dr ing. Thecoating may also be applied wit a brush instead of by dipping. -Theintermediate drying between the two dippings or treatments abovedescribed may be omitted in certain cases. 'The sheets so produced willform perfect stencils when written on by an ordinary typewriting machineor stylus when of duplicate copies by placing the stencils on surfacesto be printed andrunningan so formed is so delicate that the coatingmaterial can be displaced when dry by a type blow without cutting orbreaklng the fibers of the paper. It is yet strong enough and cohesiveenough to prevent the ink passing through portions of the paper notstruck by the type faces.- It is so responsive; to impressions that thestencils may be formed by the type striking through an ordinary inkribbon. The advantage of this flatter process is that the stencil soformed is outlined in ink and clearly legible, in fact it looks. likeordinary'typewriting so that the operator can always tell at a glance.what stencil he is using in making the duplicates or in filing orcorrecting the stencils, while it is difficult to read a stencil formedby blows of the bare type face except by holding it up to the light, andwhen animal gelatin is used as the principal sheet before the stencilbecomes at all legible. The particular function of the formaldehydeapparently is the preservation of the coating from decay so that thesheet remains usable for a long period of time. It also coagulates the,colloid and thus renders the coating more permanent and reaiatantagainst mechanical disintegration dry, and can be used to producethousands ably raised to the boiling point and about may be given asecond dipping or coating ordinary ink roller over them. The coating .85

base, it is absolutely necessary to wet the and the dissolving action ofthe oils of the inks used in duplicating machines. If other colloids areused with the Irish moss, the formaldehyde has of course, the samebeneficial effect on t em. The formaldehyde can be dispensed with whenthe stencils are to be used up quickly.

The advantages of my invention as at present understood are due to thefact that the Irish moss, being soft, requires a less quantity ofglyerin to reduce it to the proper film forming consistency, and to thefact that it also forms a film more impervious to fluids. It isadvantageous to reduce the amount of glycerin, because'a largeproportion of that ingredient is apt to give the film an undesirablestickiness, an as it is not fixed or set by the coagulating agent, itspresence in considerable quantity detracts from the permanence of thecoating. The characteristic advantage which permits a stencil inaccordance with my invention to be formed without previous wetting isdue to the softness of the Irish moss coating while it is stillimpervious to liquids, and to its spongy quality which permits it toabsorb and hold a'large quantity of water. In this regard the Irish mossis vastly superior to animal gelatin when used as the principal base ofa coating which on exposure to the atmosphere gives up its moisture andhardens to an extent which requires a sheet coated with it to bethoroughly saturated with water before it can be stencilized on atypewriting machine. Another great advantage in the use of Irish moss isdue to the fact that its characteristic constituent, car-- rageenin, isa pectin like a mucilage, and not, a gelatin. Gelatin is a nitrogencontaining body, being 17 to 18 per cent. nitrogen, and is a proteid.-.Carrageenin, on the other hand, is a saccharo-colloid and contains nonitrogen. Like gelatin, it forms a elly with water but the jellyproduced from Irish moss has difi'erent characteristics from that formedfrom animal gelatin in that it has a permanent softness andwater-holding and retaining power which is highly beneficial in acoating of this character. Irish moss is a natural film orcoating-producing material and is much more effective in this way thananimal gelatin heretofore used as the principal base for that purpose inmaking typewritten stencils. That is to say, gelatin dissolved inseveral times its weight of water will readily pass through a finesieve, or through a sheet of Yoshino paper, but Irish moss, thoughdissolved in forty times its weight of water so as to produce a verydilute solution, will notpass through the same sieve, or through theYoshino paper, but collects thereon in a film or coating. This isprobably due to the fact that the Irish moss produces solutions of muchgreater body or viscosity for given degrees of concentration than doesgelatin, which results from the dissolved molecules or aggregates beinglarger, which retards their penetration of any sieve-like structure.Consequently a given thickness of coating can be produced on a sheet ofYoshino paper with a more completely hydrated solution when Irish mossis used, than when gelatin alone is employed. Such hydrated coating canbe displaced by type pressure to form a stencil without the ap licationof external moisture, and as the Irish moss has the spongelike capacityfor retaining the water of hydration for a long period, the abovedescribed condition persists under ordinary atmospheric conditions andthe sheet can be used for stencil making at any time.

Having, therefore, described my invention, I claim:

1. A stencil comprising a sheet of thin paper of loose texture coatedwith a coagulated colloidal film of vegetable origin, and great moistureretaining capacity.

2. A stencil comprising a sheet of thin paper of loose texture treatedwith a coagulated solution of Irish moss.

3. A stencil sheet formed of paper of loose texture coated with a filmincluding a coagulated colloid of vegetable origin and great moistureretaining capacity andglycerm.

4. A stencil sheet formed of paper of loose texture coated with acoagula'ted film including Irish moss and glycerin.

5. A stencil sheet composed of paper of loose texture treated with asolution including a colloid of vegetable origin and great moisture.retaining capacity and formaldehyde. 1

'6. A stencil sheet composed of paper of loose texture coated with afilm including Irish moss, glycerin and formaldehyde.

7. As an article of manufacture for use in forming stencils, a sheet ofYoshino paper coated with a film including a colloid of vegetable originand great moisture retaining capacity, glycerin and formaldehyde.

8. A sheet adapted to be stencilized by type pressure comprising a sheetof thin paper of loose texture treated with a coagulated solution of acolloid of vegetable origin, and great moisture retaining capacity.

9. A sheet adapted to be stencilized by type pressure comprising a sheetof thin paper of loose texture treated with a coagulated solution ofIrish moss.

FRANK D. BELKNAP.

Witnesses A. PARKER-SMITH, M. G. CRAWFORD.

